1. Technical Field
The present invention relates generally to the field of housings for electrical apparatus and more specifically to a housing incorporating a safety structure for preventing an operator from accidentally contacting hazardous sources of electrical energy within the housing.
2. Description of the Background Art
A current trend in the design of electrical and electronic systems is to modular system configurations wherein individual electrical units of the system are readily accessible and in some cases customer removable. The use of modular designs provides a number of different advantages. Manufacture and assembly is made simpler in that each unit can be manufactured and tested separately before being assembled in the complete system. Furthermore, if a removable unit becomes defective, it can be readily removed for repair and replaced with a working device.
A typical multi-component system of this type is a data processing system in which data storage devices, processing hardware, power supplies and cooling fans are contained within a single housing. Typically, the removable data storage devices will be mounted within a first compartment of the housing which is separated by an internal bulkhead from a second compartment in which are located the processing hardware, power supplies etc. Provision of power and control signals to each of the devices is effected via connectors mounted in the bulkhead which mate with one or more connectors at the rear of each device.
In a system housing of the type described above including internal power connectors, it is necessary to prevent a system operator from accidentally coming into contact with hazardous electrical sources (e.g., exposed voltages) within the housing. Therefore, it is necessary to ensure that the high energy connector pins are not accessible to the operator's fingers. This requirement can be directly achieved either by providing the power connector with a shroud or recessing the pins in the connector, thereby rendering the pins inaccessible. Alternatively the problem can be avoided by designing the connector with female contacts. However in many situations it will not be practicable for reasons of space or economy to provide either connector shrouding or female power connectors. In these situations alternative solutions are needed.
One known solution is to provide a removable grill structure at the front of the housing and in front of the electrical units which protects the operator from accidental contact with the live connector(s) within the housing. Although this provides the necessary protection, it is necessary to remove the grill each time it is desired to gain access to the housing cavity to plug or unplug the devices. The additional cost involved in providing such a grill is a further disadvantage. Alternative techniques, e.g., the provision of a shutter arrangement at the front of the housing, suffer from the same disadvantages in that they do not allow the operator access to load or unload the devices while at the same time providing the necessary protection.